My institution recently switched from its home-grown electronic medical record to EPIC, an EMR for which many great things have been promised. Indeed, it is a considerable improvement over the past system. A number of hopes have been pinned on the latest-generation EMRs, not the least of which is the idea that finally, with this newest generation of tools, a nexus can be created and sustained among comparative effectiveness research (i.e., the branch of medical science that asks which treatment are better and why), clinical care, electronic records, and patient-reported outcomes. A very recent article by my senior colleague in the School of Public Health, Albert Wu, and colleagues, traces the genealogy and current outlines of this nexus - and advises what might be necessary to move this opportunity forward.One point he doesn't raise in his article, however is which patients are actually using such EMRs. I was talking to a colleague the other day, and asked him idly what proportion of our patients had "activated" the code they were sent to access their patient portal into the EMR. "Twenty percent," he sang out, and then, perhaps noting my shocked expression, quickly added, "But that's good!"I don't know how good that is, but - for whatever reason - I can't find much recent scientific literature on the prevalence of patient activation of such portals in recent years. However, a study conducted in New York City in the year 2010 published in the Journal of General Internal Medicine presents some interesting figures. Namely, that 16% of all patients in the study received an access code, and of these, 60% activated their code. Disparities were noted: those who activated their access tended to be whiter, English-speakers, and with private insurance.Similar reports are available elsewhere, though not seemingly from much more recently [as always, I would love getting updates and will happily correct in this space]. The question remains: in any given practice, how do we make sure that the patients who are actually using the EMR faithfully reflect the composition of the entire population? If we do not somehow make these portals widely available, without disparities or inequities, we risk doing what doctors have always done: thrust health interventions at their patients without regard for accessibility or patient-centeredness, and then act cynical or walk away when patients do not snap it up with alacrity.